Noise impairments such as composite triple beats (CTB), composite second order beats (CSO) and snow noise (SNOW) are found in substantially all television sights transmitted by cable.
Various methods and systems for measuring of the impairments in TV signals have been proposed, for example, U.S. Pat. No. 5,221,967 issued Jun. 22, 1993 to Ward et al. discloses a system for retching (classifying) and monitoring impairments in cable television sights by frame grabbing and producing a two dimensional Fourier transform of the frame to reveal the impairments and their type. U.S. Pat. No. 5,329,311 issued Jul. 12, 1994 to Ward et al. discloses a system for determining the SNOW noise content of a video signal by grabbing and digitizing a video frame, filtering the digitized signal and subdividing it into subimages and determining the noise signal in each subimage to determine the noise in the signal and if desired the carrier to noise ratio.
U.S. Pat. No. 5,323,239 issued Jun. 21, 1994 to Ward et al. discloses a system for correcting a cable TV signal to reduce the CTB impairments by digitizing and dividing a frame into a plurality of stripes to estimate the amount of the impairment contained in the signal and then subtract that amount from the stripe and then reassemble the stripes.
Accurate method for measuring these impairments, particularly the measurement of CTB that provides an effective means for the cable comply to detect a problem without interfering with the projected or transmitted picture would be a significant advantage. Also a system that can measure all of the different noises CTB, CSO and/or SNOW is not prodded by the above described patented systems. The above systems also require a significant amount of computing power and a system that requires relatively small amount of processing would provide an added advantage of significant value.